The aim of the current study is to determine the fish biodiversity in the shallow waters (0 - 20 m) of Gokceada in the North Aegean Sea. The samples were collected monthly between June 2013 - June 2014 using by a beach seine (0 - 2 m) and beam trawl (5 - 20 m). Field sampling was carried out in two stages. A preliminary sampling survey was carried out in the first phase (March-April 2013). During this period, sampling was conducted in each station around the entire island where sampling gear was feasible to use, and the most productive sampling stations were determined. The second stage was the biodiversity monitoring work. During the study period, 13-monthly sampling surveys were carried out at six seine and dredge stations around the island. During the whole period, a total of 30509 individuals belonging to 80 species were sampled. From the seine samplings (0-2 m), 18702 individuals from 40 species were obtained. The beam trawl samplings (5-10 and 10-20 m) identified 11807 individuals from 66 species. Biodiversity indices were calculated, and species diversities and abundances were determined for the seasons. The most copious seasons in terms of number of species abundance was identified in fall and summer. Fish species diversity and abundance maps were generated for each station. As a result, it was determined that the coastal ecosystems of Gokceada, northern Aegean Sea, incorporated many important habitats that is rich in biodiversity. In addition, many commercial species that had been over-exploited in the region was determined to use these coastal habitats for feeding, breeding, sheltering, and growing.